Process of making camphor.



JPatented May 23, 1905.

v UNITED STATES PATENT QFFICEY KARL STEPHAN AND PAUL HUNSALZ, OF BERLIN, GERMANY, ASSIGNORS TO OHEMISOHE FABRIK AUF AOTIEN, (VORM. E, SOHERING OF BERLIN,

GERMANY.

PROCESS OF MAKING CAlVlPHOR- SPECIFIOATION fQrming part of Letters Patent No. 790,601, dated May 23, 1905.

Application filed December 21, 1904. Serial No. 237,831.

To all whom, it mlaly concern:

Be it known that we, KARL STEPHAN and PAUL HUNSALZ, chemists, subjects of the German Emperor, residing at the city of Berlin, Kingdom of Prussia, German Empire, have invented a new and useful Improvement in Processes of Producing Oamphor from Isoborneol Esters, of which the following is aspecifieation.

Our invention relates to the manufacture of camphor by oxidizing isoborneol esters. The

use of these esters in place'of isoborneol.

itself has the great advantage that the saponifieation of the esters which are formed in the production of isoborneol from camphene is avoided.

The oxidation may be performed, for instance, by means of chromic acid, nitric acid, permanganate, manganese, and sulfuric acid, Oaros acid, 620., working either in solution or in suspension. 1

Example 1: One hundred and twentyseven parts, by weight, of isobornyl acetate aredissolved in two thousand parts, by Weight, of glacial acetic acid or another suitable acid which is not aifected by the oxidizing agent and then oxidized with seventy-eight parts, by

weight, of chromic acid. The reaction being cooling, the raw camphor crystallizes out and is then purified in the usual way.

Of course instead of free chromic acid equivalent quantities of chromates and acids may be employed.

The reaction proceeds in an analogous manner if other oxidizing agents are used. In place of isobornyl acetate other isobo'rnyl esters may also be usedfor instance, the benzoate or the formiate, &c.; but the acetate is preferable on account of its greater accessibility.

If, for instance, isobornyl benzoate be em ployed, the process is carried out as follows:

Example 3: One hundred and seventy parts, by Weight, of isobornyl benzoate are well mixed with seventy-eight parts, by weight, of chromic acid in two thousand parts, by weight, of water at a temperature of about 90 centigrade for so long as no more free chromic acid can be identified. After cooling the formed raw camphor is separated from the adhering benzoic acid by boiling with alkalie's and is further purified in the usual way.

We claim as our invention a 1'. The process of producing camphor, which consists in directly oxidizing isoborneol ester and isolating the camphor so formed, substantially as set forth.

2. The process of producing camphor, which consists in oxidizing 'isoborneol acetate and isolating the camphor so formed, substantially as set forth.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

' KARL STEPHAN. PAUL HUNSALZ. Witnesses:

HENRY HASPER, WOLDEMAR HAUPT 

